A. Field of the Invention
The invention relates generally to devices for controlling and monitoring liquid levels.
B. Background
There are numerous varieties of devices and systems being used for the monitoring and control of fluctuating levels of fluids in vessels. Many of these devices use the conductive properties of the fluids contacting probe mounted contact points to cause a predetermined action by devices through the opening or closing of electrical circuits in response to the detected conduction in the fluid. Probes of different types suspended in the vessel and cut to a predetermined length for contact with the fluids are widely used. These probes are connected to devices outside the vessel with electrical circuits to terminals of control devices. See, for example, the control system supplied by Turner Controls, Inc., a copy of which is attached to this application. Further, see U.S. Pat. Nos. 3,759,286 to Page; 3,605,798 to Green, et al; 3,224,638 to Harrell, Jr; 2,766,406 to Schwarzkoff; 2,433,599 to Cohen; and 1,699,143 to Hill. Of these, Page, like a suggestion made to Mr. Charles Morgan by Mr. Larry Brown before the invention herein, shows a side mounted intrusive device through piping for swimming pool use. Mr. Brown had suggested using screws through the side of a water tank, or PVC pipe connected to it. Another person also suggested using epoxy and filings from the material to be sealed for viscosity for a sealant for intrusive device.
However, none of the art discloses incorporation of the electrical terminals directly through the vessel walls to permit precise level controls without the use of externally mounted probe holders for the contact probes inside the vessel, which require removal and modification for changes and/or additional devices, nor methods for sealing penetration of the terminals through the vessel walls to attain a fluid tight, as well as pressure tight device. Further, none of the art discloses a device as described above which allows also the capability of visual monitoring of the condition of the fluid in the vessel as well as the level of said fluid. This probeless method system permits easy and quick change of level of detection from outside the vessel to cause control action. Further, the use of a probeless level controller has the advantages of:
1. No guess work in cutting wires and attaching probe holders in attempting to achieve precise distances between control points on initial installations, adjusting operating levels and adding new equipment;
2. No "shutdown" time needed to disassemble and make changes, or to repair shorted probes or probe holders, or probes that become disengaged;
3. No water or condensate causing false signals from conventional probe holders, which arises frequently in inclement weather on systems using exterior mounted probe holders;
4. No exotic parts of machined pieces incorporated into construction that cause extended "shutdown" time for replacement if damaged;
5. No substantial difficulty with mounting inside a remote control building or outside with an optional heater and/or insulated box for protection against the elements; and
6. Regular cleaning may be accomplished by disconnecting a pipe union, removing a bushing in the bottom unit, washing with a sponge or brush, and flushing clean. Done on a regular basis, it should only require ten to fifteen minutes each time. (This is a very critical item due to the many minerals that collect on probe systems, which require much more down time periodically to clean or replace corroded probes. In many cases of system failure to operate in automatic mode, it is not the controller, but corroded or shorted probes.)
7. Ability to visually inspect quality and condition of fluids in the vessel, as well as visually check operation of automatic devices connected to system.
8. Ability to withdraw representative samples of fluid of the vessel directly from the controller piping.